Welding detection apparatus and welding detection method

Abstract

A welding detection apparatus is used for detecting a weld seam between a case and a top cover of a battery, and includes: an image acquisition component configured to shoot the weld seam, the image acquisition component being located obliquely above an outer side of the weld seam and forming an included angle with a height direction of the battery; and a controller configured to obtain a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between the image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and the included angle, and compare the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified.

What is claimed is: 
     
         1 . A welding detection apparatus for detecting a weld seam between a case and a top cover of a battery, the detection apparatus comprising:
 an image acquisition component configured to shoot the weld seam, the image acquisition component being located obliquely above an outer side of the weld seam and forming an included angle with a height direction of the battery; and   a controller configured to obtain a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between the image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and the included angle, and compare the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified; and configured to establish at least one plane parallel to the outer side wall of the case in an image to intersect with the weld seam to obtain an intersecting line which is a contour line of a surface of the weld seam, fit a spatial line by taking a plurality of points on the intersecting line, calculate a distance between each of the plurality of points on the intersecting line and the spatial line, and compare the distance with a preset distance threshold to determine whether an appearance defect exists in the weld seam.   
     
     
         2 . The welding detection apparatus according to  claim 1 , wherein the battery is provided with one image acquisition component on each of two sides along a width direction of the battery, and the image acquisition component is configured to move along a length direction of the battery relative to the weld seam in a detection process. 
     
     
         3 . The welding detection apparatus according to  claim 1 , wherein the controller is configured to:
 determine that the protruding height of the weld seam is unqualified in a case that a plurality of positions with the protruding height exceeding the preset height threshold exist on the weld seam within a first preset distance range in an extension direction of the weld seam and the number exceeds a preset value.   
     
     
         4 . The welding detection apparatus according to  claim 1 , wherein the controller is configured to select a maximum value of the protruding height of the weld seam in the height direction at the same position in the extension direction of the weld seam. 
     
     
         5 . The welding detection apparatus according to  claim 1 , wherein the reference surface area is preset to be spaced apart from the weld seam in the height direction. 
     
     
         6 . The welding detection apparatus according to  claim 1 , wherein the controller is configured to divide the weld seam into a plurality of detection areas in the extension direction of the weld seam, fit a sub-reference surface area corresponding to each detection area on an outer surface of the case, and select the corresponding sub-reference surface area for calculation when the protruding height of the weld seam in each detection area is obtained. 
     
     
         7 . The welding detection apparatus according to  claim 1 , wherein the controller is configured to:
 determine that the appearance defect exists in the weld seam in a case that points with the distance exceeding the preset distance threshold consecutively exist on the weld seam within a second preset distance range in the extension direction of the weld seam.   
     
     
         8 . The welding detection apparatus according to  claim 1 , wherein the controller is configured to determine a type of the appearance defect in the weld seam according to a deviation direction and positions of the points with the distance exceeding the preset distance threshold relative to the spatial line in a case that the appearance defect exists in the weld seam. 
     
     
         9 . A welding detection method for detecting a weld seam between a case and a top cover of a battery, the welding detection method comprising a weld seam protruding height detection step and a weld seam appearance defect detection step, wherein:
 the weld seam protruding height detection step comprises:
 obtaining a protruding height of the weld seam relative to a reference surface area on an outer side wall of the case according to a first distance between an image acquisition component and the outer side wall of the case, a second distance between the image acquisition component and the weld seam, and an included angle, wherein the image acquisition component is configured to shoot the weld seam, and the image acquisition component is located obliquely above an outer side of the weld seam and forms the included angle with a height direction of the battery; and 
 comparing the protruding height with a preset height threshold to determine whether the protruding height of the weld seam is qualified; and the weld seam appearance defect detection step comprises: 
 establishing at least one plane parallel to the outer side wall of the case in an image to intersect with the weld seam to obtain an intersecting line which is a contour line of a surface of the weld seam; 
 fitting a spatial line by taking a plurality of points on the intersecting line, and calculating a distance between each of the plurality of points on the intersecting line and the spatial line; and 
 comparing the distance with a preset distance threshold to determine whether an appearance defect exists in the weld seam. 
   
     
     
         10 . The welding detection method according to  claim 9 , wherein comparing the protruding height with the preset height threshold to determine whether the protruding height of the weld seam is qualified comprises:
 determining that the protruding height of the weld seam is unqualified in a case that points with the protruding height exceeding the preset height threshold consecutively exist on the weld seam within a first preset distance range in an extension direction of the weld seam.   
     
     
         11 . The welding detection method according to  claim 9 , wherein a maximum value of the protruding height of the weld seam in the height direction is selected at the same position in the extension direction of the weld seam. 
     
     
         12 . The welding detection method according to  claim 9 , wherein selecting the reference surface area on the outer side wall of the case comprises:
 selecting the reference surface area to be spaced apart from the weld seam in the height direction.   
     
     
         13 . The welding detection method according to  claim 9 , wherein the weld seam protruding height detection step further comprises:
 dividing the weld seam into a plurality of detection areas in the extension direction of the weld seam;   fitting a sub-reference surface area corresponding to each detection area on an outer surface of the case, the reference surface area comprising a plurality of sub-reference surface areas; and   selecting the corresponding sub-reference surface area for calculation when the protruding height of the weld seam in each detection area is obtained.   
     
     
         14 . The welding detection method according to  claim 9 , wherein comparing the distance with the preset distance threshold to determine whether the appearance defect exists in the weld seam comprises:
 determining that the appearance defect exists in the weld seam in a case that points with the distance exceeding the preset distance threshold consecutively exist on the weld seam within a second preset distance range in the extension direction of the weld seam.   
     
     
         15 . The welding detection method according to  claim 9 , wherein the weld seam appearance defect detection step further comprises:
 determining a type of the appearance defect in the weld seam according to a deviation direction and positions of the points with the distance exceeding the preset distance threshold relative to the spatial line in a case that the appearance defect exists in the weld seam.